There are known sliding rails of this type, in which the base of the support is attached to the bottom of the fixed section by a rivet placed between one end of the adjusting screw and the recess in said base.
This arrangement has several disadvantages:                the rivet represents an additional cost,        for a given position of the recess in the bottom of the sliding rail (position which is generally dictated by the vehicle manufacturer), the length of the adjusting screw is limited by the presence of the rivet, and therefore the range of possible sliding rail travel is also limited.        